1. Technical Field
The present invention relates to an ultrasound system and a method of forming an ultrasound image.
2. Background Art
An ultrasound system has become an important and popular diagnostic tool due to its non-invasive and non-destructive nature. Modern high-performance ultrasound imaging diagnostic systems and techniques are commonly used to produce two- or three-dimensional images of internal features of patients.
Generally, the ultrasound system includes a probe, a beam former, a signal processing unit, an image processing unit and a display unit. The probe, which transmits and receives ultrasound signals, contains a plurality of transducer elements for reciprocally converting the ultrasound signals and the electrical signals. Each of the transducer elements in the probe may individually generate an ultrasound signal or several transducer elements may generate ultrasound signals at the same time. The ultrasound signals may be reflected from discrete planes (i.e., surfaces of reflectors) of acoustic impedance in the target object. The transducer elements may be operable to convert the received ultrasound echo signals into electrical receive signals. The beam former may be configured to apply delays to the electrical receive signal by considering positions between focal points and respective transducer elements to form a receive-focused beam. The signal processing unit performs analog-to-digital conversion, amplification and signal processing upon the receive-focused beam. The image processing unit may be operable to form an ultrasound image based on the signals outputted from the signal processing unit. The display unit may be configured to display the ultrasound image.
The Doppler effect is used in the ultrasound system to provide a color flow image showing velocity information of reflectors in the target object. The color flow image not only provides real-time blood flow visualization, but it can also accurately delineate a wide range of blood flow conditions, ranging from high velocities in large vessels to minute trickles coursing through small vessels.
The conventional ultrasound image may merely provide a color flow image showing velocity information of reflectors in the target object without indicating any velocity changes of the reflectors in the target object. Thus, it is difficult for the user to intuitively recognize the velocity change of the reflectors in the target object.